Hadoop配置datanode无法连接到master

共计 2077 个字符，预计需要花费 6 分钟才能阅读完成。

初次在 VM 上配置 Hadoop，开了三台虚拟机，一个作 namenode,jobtracker

另外两台机子作 datanode,tasktracker

配置好后，启动集群

通过 http://localhost:50700 查看 cluster 状况

发现没有 datanode

检查结点，发现 datanode 进程已经启动，查看 datanode 机器上的日志

2014-03-01 22:11:17,473 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Master.hadoop/192.168.128.132:9000. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

2014-03-01 22:11:18,477 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Master.hadoop/192.168.128.132:9000. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-01 22:11:19,481 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Master.hadoop/192.168.128.132:9000. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
2014-03-01 22:11:20,485 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Master.hadoop/192.168.128.132:9000. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

2014-03-01 22:11:21,489 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: Master.hadoop/192.168.128.132:9000. Already tried 4 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

发现 datanode 无法连接到 master , 但是经过尝试，可以 ping 通，到结点查看，9000 端口也处于监听状态，百思不得其解

最终发现 core-site.xml 中

    <property>
        <name>fs.default.name</name>
        <value>hdfs://localhost:9000</value>
  </property>
才意识到监听 127.0.0.1 端口，并不能被外机访问

改为主机名，一切正常

<property>
        <name>fs.default.name</name>
        <value>hdfs://Master.Hadoop:9000</value>
  </property>

相关阅读 ：

Ubuntu 13.04 上搭建 Hadoop 环境 http://www.linuxidc.com/Linux/2013-06/86106.htm

Ubuntu 12.10 +Hadoop 1.2.1 版本集群配置 http://www.linuxidc.com/Linux/2013-09/90600.htm

Ubuntu 上搭建 Hadoop 环境（单机模式 + 伪分布模式）http://www.linuxidc.com/Linux/2013-01/77681.htm

Ubuntu 下 Hadoop 环境的配置 http://www.linuxidc.com/Linux/2012-11/74539.htm

单机版搭建 Hadoop 环境图文教程详解 http://www.linuxidc.com/Linux/2012-02/53927.htm

搭建 Hadoop 环境（在 Winodws 环境下用虚拟机虚拟两个 Ubuntu 系统进行搭建）http://www.linuxidc.com/Linux/2011-12/48894.htm

更多 Hadoop 相关信息见 Hadoop 专题页面 http://www.linuxidc.com/topicnews.aspx?tid=13